A number of pulley-based exercise devices exist in the market. Many of these devices are designed to be anchored to a door, doorknob, or bed post. These devices typically comprise two pulleys and a rope, with two hand grips (one attached at each end of the rope, such as shown in U.S. Pat. No. 5,171,295 to Schwalm) or with a hand grip and a weight (one attached at each end of the rope, such as shown in U.S. Pat. No. 4,229,002 to Masters). Vigorous exercises typically cannot be performed with these devices because, among other things, the anchor is too weak or the rope would rub excessively on the sides of one or both of the pulleys. Also, these devices are compatible with an undesirably limited number and variety of exercises because only a few body positions may be assumed with respect to the devices and because the devices may be used in only a few configurations. Additionally, many of these devices are not easily portable, cannot be attached to a wide variety of horizontal and vertical structures, and cannot support a person's full body weight.
Attempts have been made to strengthen the anchors of pulley-based exercise devices and to increase the number and variety of exercises that may be performed with them. One example is disclosed in U.S. Pat. No. 4,060,240 to Dunston, which comprises a single pulley and a rope. These attempts, however, have not provided a satisfactory solution to the problems that are involved in the prior art.
Accordingly, there is a need for a pulley-based exercise device that is compatible with a wide variety of exercises and body positions, can withstand the forces of vigorous exercise, can be used in many configurations, and can be attached to most any vertical or horizontal support. The present invention satisfies this and other needs, and provides further related advantages.